Immovable capital goods in medieval Muslim lands: why water-mills and building cranes went missing

Immovable capital goods such as water-mills were in widespread use in Muslim lands in the early medieval period, just as in the Latin West. In the later Middle Ages, however, vertical windmills and cranes, then widely employed in Europe, were not introduced there, while the number of water-mills dwindled. This decline was concentrated in specific parts of the Muslim world, which rules out time-invariant and generic causes like religion. We show that it was the growing insecurity of property rights and introduction of a specific system of land tenure (ikta) that prevented application of such labor-saving capital goods.